1. Field of the Invention
The present invention generally relates to a composite article that has excellent impact strength and fire resistance. More specifically, the present invention relates to a composite article having layers that provide the composite article with impact and fire resistance.
2. Description of the Prior Art
Fire-rated glass and windows are known for use in the residential, commercial, and industrial construction industries, as well as the consumer appliance and automotive industries, for preventing fire, smoke, or extreme heat from propagating through buildings or to contain heat or fire within a space, such as in an oven. Fire-rated glass and windows are typically rated for either 30, 60, 90, or 120 minutes, depending on how long it takes for the fire-rated glass and windows to fail when the fire-rated glass and windows are exposed to a predefined fire condition leading to an exposure temperature of 843° C. after 30 minutes, 926° C. after 60 minutes, 1010° C. after 120 minutes, and 1093° C. after 240 minutes from startup. For example, a 30 minute rated glass or window fails when the window is exposed to the above predefined fire condition for a period of over 30 minutes. Possible measures of failure can include through-holes that allow flame penetration, evolution of hot gas capable of igniting cotton balls on a side of the glass or window that is not directly exposed to the fire condition (i.e., an unexposed side of the glass or window) at a certain distance from the glass or window, flame appearing and lasting on the unexposed side of the glass or window, outer side temperature exceeding requirements, or collapse of the glass or window under hose stream impact, depending on the specification of a particular rating in a particular geographic location.
Much work has been done to develop fire-rated glass and windows that have sufficient fire-ratings. The fire-rated glass is typically formed from a series of layers, including conventional glass layers and a layer that provides the fire resistance to the glass. Many different materials have been used to form the layer that provides the fire resistance; however, many of the materials used to form the layer that provides the fire resistance have shortcomings. For example, when carbon-based materials, especially primarily carbon-based materials having more than 50 parts by weight carbon, based on the total weight of all molecules in the material, are used to form the layer that provides the fire resistance, the materials will eventually emit excessive amounts of smoke and toxic gases.
Other non-carbon based materials that will not emit as much smoke and toxic gases, as compared to when primarily carbon-based materials are used, have also been used for the layer that provides the fire resistance. For example, inorganic silicon-based materials have been used in the layer that provides the fire resistance in the fire-rated windows. Specific examples of inorganic silicon-based materials include alkali metal polysilicate hydrate, as disclosed in U.S. Pat. No. 6,159,606 to Gelderie et al., a composition obtained through hydrolysis and condensation of silicates, as disclosed in U.S. Pat. No. 5,716,424 to Mennig et al., and a silicone elastomer, as disclosed in German Patent Application No. 2826261. Although the inorganic silicon-based materials will char, the inorganic silicon-based materials produce less smoke and toxic gas, as compared to primarily carbon-based materials. However, existing fire-rated windows including layers formed from the silicon-based materials are extremely labor intensive to fabricate, heavy, and sometimes insufficiently able to maintain structural integrity upon failure under heat. More specifically, once the breach forms in the fire-rated windows due to heat, the fire-rated windows are prone to mechanical failure. Similar deficiencies exist for other applications where fire protective or resistant transparent articles are used. Examples include fire rated doors and curtain walls.
Due to the deficiencies of the existing fire-rated glass and windows, it would be advantageous to provide a composite article having excellent impact strength and fire resistance that is lighter in weight, is easy to fabricate, and maintains excellent structural integrity even after failure of the composite article under heat.